Description
The 5V Normally Open Shock Sensor Relay Module is a specialized vibration and impact detection device designed for industrial equipment protection, security systems, and automation applications. Operating on a standard 5V DC supply—compatible with USB power, Arduino, Raspberry Pi, and other microcontroller platforms—this module combines a highly sensitive piezoelectric shock/vibration sensor with a built-in relay that activates when physical impact or excessive vibration is detected.
Unlike continuous monitoring modules, this device features a Normally Open (NO) relay configuration, meaning the relay remains open (inactive) under normal conditions and closes (activates) only when a shock event occurs. This makes it ideal for fail-safe alarm systems, emergency shutdown circuits, and equipment tamper detection. The module includes an adjustable sensitivity potentiometer, allowing you to set the precise impact threshold required for triggering, from light taps to heavy shocks.
The onboard LM393 comparator processes the sensor signal and provides clean, bounce-free triggering. A green LED indicator confirms relay activation, and the module offers both NO and NC output terminals for flexible integration into existing control systems. The sensor element is compact and can be mounted remotely on vibrating machinery, doors, windows, or structural elements.
Whether you need to protect CNC machines from excessive vibration, detect unauthorized access to equipment cabinets, monitor conveyor belt jams, trigger alarms during seismic events, or provide impact detection for industrial robots, the 5V Shock Sensor Relay Module delivers reliable, standalone protection without requiring complex programming or PLC integration.
Key Features
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Normally Open (NO) Default State – Relay remains open (inactive) until shock is detected; ideal for fail-safe alarm and shutdown applications.
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Adjustable Sensitivity – Onboard potentiometer allows precise setting of impact/vibration threshold, from light taps to heavy shocks.
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5V DC Operation – Compatible with USB power, Arduino, Raspberry Pi, and standard 5V power supplies.
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Piezoelectric Shock Sensor – Fast response to physical impacts and vibrations; solid-state design with no moving parts.
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LM393 Comparator IC – Provides stable, noise-immune threshold detection with adjustable hysteresis.
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Built-in SPDT Relay – Controls external devices up to 10A / 250V AC or 10A / 30V DC.
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Dual Output Terminals – Both NO (Normally Open) and NC (Normally Closed) available for flexible wiring.
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Status Indicator LED – Green LED illuminates when relay is activated (shock detected).
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Compact Design – Small footprint for easy installation inside control panels, equipment enclosures, or security housings.
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Latching/Non-Latching Operation – Relay can be configured to latch (stay on after detection) or auto-reset (depending on module version).
Technical Parameters
Usage Guide
How It Works
The piezoelectric sensor continuously monitors for mechanical vibration and impact. When a shock exceeds the user-adjustable threshold, the sensor generates a voltage spike. The LM393 comparator processes this signal and triggers the relay. Because the default state is Normally Open, the relay closes (activates) only when a shock is detected, making it perfect for alarm triggering, equipment shutdown, or event notification.
Wiring Instructions
Step 1 – Power Connection
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Connect a 5V DC power supply to the VCC (+) and GND (-) terminals.
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Suitable sources: USB charger, 5V power adapter, Arduino 5V pin, or regulated 5V battery pack.
Step 2 – Load (Device) Connection
Wiring Example (Alarm Siren – Turns ON when shock detected):
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Connect alarm siren’s positive wire → NO terminal
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Connect 5V power supply positive → COM terminal
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Connect alarm siren’s negative → power supply negative directly
Wiring Example (Equipment Shutdown – Turns OFF machine on shock):
⚠️ Safety Warning: For AC loads (110V/220V), ensure all connections are properly insulated. Use appropriate gauge wire and mount the module in an enclosure.
Sensitivity Adjustment
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Power on the module with the sensor mounted in the target location.
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Use a small screwdriver to adjust the potentiometer on the board:
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Test by applying controlled taps or vibrations to the sensor.
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The green LED illuminates when the relay activates.
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Adjust until the desired sensitivity is achieved.
Sensor Mounting Tips
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Mount the sensor firmly to the equipment or surface being monitored using screws, adhesive, or double-sided tape.
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For best sensitivity, mount on a rigid, flat surface—not on flexible panels that may dampen vibrations.
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Avoid mounting near sources of constant vibration (e.g., motors) that may cause false triggering unless intentional.
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The sensor can be mounted remotely using 2-conductor wire up to 5 meters (16 feet).
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For outdoor or wet environments, enclose the sensor in a waterproof housing.
Testing the Module
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Apply 5V power – the module LED may remain off (normal state).
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Tap the sensor gently with a finger or small tool.
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The relay should click and the green LED should illuminate for a short duration.
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After the shock subsides, the relay should return to the open (off) state (non-latching version) or remain latched until reset (latching version).
Q: What does "Normally Open" (NO) mean for this module?
“Normally Open” means the relay contacts are open (no electrical connection) under normal, no-shock conditions. When a shock is detected, the relay closes (connects) the COM and NO terminals, completing the circuit and activating your connected device (alarm, light, etc.). This is the opposite of “Normally Closed” modules, which are on by default and turn off when triggered.
Q: What is the difference between NO and NC outputs on this module?
Both terminals are available on the same module—use whichever suits your application.
Q: Can this module detect continuous vibration, or just impact?
The piezoelectric sensor responds to changes in vibration and impact. For continuous vibration (e.g., a running motor), the sensor may trigger repeatedly. For applications requiring continuous vibration monitoring (e.g., pump bearing wear detection), a dedicated vibration transmitter module is recommended.
Q: What types of loads can I control with this relay?
The 10A relay can control:
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AC loads: Fans, lights, small pumps, solenoid valves, alarms (up to 250V AC, 10A)
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DC loads: LED lights, DC motors, buzzers, PLC inputs (up to 30V DC, 10A)
Always ensure your load current does not exceed the relay rating.
Q: How do I prevent false triggering from ambient vibrations?
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Decrease sensitivity: Turn the potentiometer clockwise to require stronger shocks.
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Mount the sensor securely: Loose mounting can cause false triggers.
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Use hysteresis: Some module versions include adjustable hysteresis to ignore minor fluctuations.
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Relocate the sensor: Move away from known vibration sources.
Q: Can I use this module for both home and business applications?
Home users: Door/window break-in detection, glass break sensors, washing machine imbalance alarm, sump pump vibration monitoring, garage door tamper detection.
Business users: CNC machine vibration shutdown, conveyor belt jam detection, industrial equipment tamper protection, security cabinet intrusion detection, seismic event monitoring, pump cavitation detection, structural health monitoring.
Q: Does the relay latch (stay on) after a shock, or reset automatically?
This depends on the specific module version:
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Non-latching (pulse) version: Relay activates briefly (e.g., 0.5–5 seconds) and then resets automatically.
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Latching version: Relay stays on after detection until manually reset (by power cycling or a reset button).
Check your product specifications. For latching operation, a separate reset circuit may be required.
Q: Can I extend the sensor wires? What is the maximum length?
Yes. The piezoelectric sensor can be extended using 2-conductor shielded wire up to approximately 5 meters (16 feet) . For longer runs, signal degradation may occur. Keep sensor wires away from high-voltage cables to prevent noise pickup.
Q: What is the response time of this module?
The module responds to shocks within approximately 10 milliseconds (0.01 seconds) , making it suitable for high-speed impact detection and real-time equipment protection.
Q: Can I use this module with an Arduino or Raspberry Pi?
Yes. The module operates on 5V, making it directly compatible with Arduino 5V pins. For Raspberry Pi (3.3V logic), use a level shifter or power the module separately from a 5V supply while connecting the relay output to the Pi via a voltage divider. You can also read the relay state as a digital input.
